Mold for framing lenses in a plastic mounting



Oct. 20, 1953 H. s. FAY 2,655,692

MOLD FOR FRAMING LENSES IN A PLASTIC MOUNTING Filed April 1, 1952 .igZ

lhwmmra INVENTOR.

w a R v BYM! M ATTORNEYS Patented Oct. 20,

UNITED oFricE MOLD. FOR NsES'i PLASTIC-MOUNTING Reward; Ear... Rq h N. aseismn to;

man? K dak. C ntaur. kechest rr NJ". qo n9natiqn--, -N ws y ample, in my Patents 2559, 860 and 2;55i9,'86'1 of July 10, 1951, injections-molds adapted to auto.- matically optically-center an uncentered lens-and to mold. a thermoplastic frame around theedge of the thus opticallycentered lens;hav.e been pro-..

vided. In some applications,- however, such. as: 1

the framing of simplelmagnifiers it. is not neces-.. sary to optically center i-thelmagnifyingllensale though it is desirableto moldrasupportmgframe. around the edge. of thellensrsubstantiallyrconcen-i. trio with its peripheryandirrespective ofrvari ance in the thicknessof thelensadjacent.its.pe

riphery.

An object, therefore, of. the present. invention. is-to provide an injectionmold structure which. is adaptable to mold around: theledge. of 3111011?- optically centered lens a plasticaftameponcentric; with the periphery of the lensand irrespectiveof variance in the thicknesszofsthe lensadjacentaits. periphery.

Other objects and advantageseof. thezpresent ine. vention will be more fully. understood from:.the:.

with the accompanying drawingfin which;

Fig. 1 is an elevational;viewapartly inrsectiQn: of one embodiment of the injectionmoldof;the:

invention showing. the mold'partly open' and a1.

lens positioned therein;

Fig. 2 is a somewhat-similarView;ofithezmtdii in which the moldis partiallyclosed; nd.the lens;-

is held between claim);ri ;members; pd:

Fig. 3 is a view-corresp ndi g in: detail o:. .-ie.s;-.. land 2, showing the-mold ccmpletely clpjsed. and. the lens in the position at which the thermoplastic composition will be injected therearound to form the frame.

similar parts. are. identified; byqithersameenumerals in these drawings,

Referring to Fig. 1 there is shown an injection mold 18 comprising an upper-moldblocklljand" a lower mold block 12" which is made ingthr ee mainparts andcomprises cooperating mold'memhers is, I4 and I5. Component parts of both mold blocks II and 12 will be described hereinafter. The upper and lower mold blocks H and 12 are movable toward and away from each other for the purpose of opening and closing the mold following description when. read: -.in-, connection cavity by; a. force provided, forexample; byrthe usual hydraulic .pistons of; an injection molding. machine, not. shown. wouldccntact: respectively. surfaces/1.62:- and lliof. theupper andzlowerimoldblocks'.

The. upper. moldsblock l I comprises associated.

mold.par.ts. I 8,; l9, 24 .2%;23. Zflilizand 2]" Nu;

meral; .218 represents: the.-. gate through which: thermoplastic .compositionzmay be injected -.byan., injection molding. machine, not shown. Meme bersml 8, I9,- 21 and! 1; are .associated;t,ogetherv and" move in-hasvertieal directionas-a unit. Member 21:, in. efiect, defines a cylindenziainiwhichlmema her.- '22; isspermitteda-to moye in:- a;- ver t-icalj dinestion. Member. @2 2: is-free: to move; downwardly untilzits;Sh0u1d6IrZ'SIGIlEfifiQS. shoulder 3 l of m mber-2.2; When-themoldisopen as inEie 1', member.2:2- is=thrust..downwa'rdly.to-thepositionshown in-Ei y n insi 3xwhichis mounted-.1 a a e ture .33 in member.-2.2;; Iiheqspring 23 exerts its force between member :27; and-a plug, 24 which isimounted on aztappedholegin ol i mber 8- The lower 'face. 3240f member ZZmas anintegral' ring. '25zthereon .WhlChLQQniZaLCtSj lens when the mold .lSaClOSQd and seryesgasgtheupper clamping member and-a1so,defines.=with project on of:

member; 2;}; the-.upper-portion of;-the;inner-wall. of the molda-cayity- Mold memb rs uid 995V of; cylinder} 1 of, thelower 2.1:- mgves into andiout mold.b1ock;. I 2,.

' The lower-mold block 112.. as -statedipreyiously, mprisesithree; mainrcoactinemembe s. I13 4.

andi 1,5; Membermcomprise am a xblock 42 ha ms an. aperturejflr he eitt whic z ollo inemember;4 iisrpositioned. f em ere dof idinenost 45 isposi-ti nedin earin memb ;whichdsslidablelthereoyer.. Mounte -meme ber.- 41;: is; a hollow cylindlfiqal member. 4,6, which xt nds. upwa ds thereef-u. A metanmate .411 isalso-mounted .OIhrmem bGIPMi'. The; cylll dliicah member .4fidSL'prQV -dediwit ercounter nk. aper:

ture ;-=4;&-.=. and anothercylindrical aperture A9 of less. diameter than L-aperture, 411: extends; upward-1 throughecylinder. 14:5 butdsin-ccmmunicationwi h; aperture: 48 through .:-hole;-. 5;l The: oppositerend Of cylinder member 461 is i fiaredi out; intoa 011p:-

like depression: iz-wwhich is. in communication: members 54; is positioned; 111"]th8:CuphkQ-Spfice; 51- -and; is.-.-held in. position by rod .iigwhichv extends.- thrcugh hole 5|...ands cylindrical: aperture Meand:

with; cylindrical'aperturei .4 9.: .A:.1 e.ns:suppo is fastened at its lower end by nut 56 and spring 5! which presses against the countersunk wall of cylinder 46. The operation of this lower lens supporting member 54 will be described hereinafter.

The hydraulic. pistons It will be seen that cylinder 46 extends through both lower mold members I3 and I 4. Mold member I4 i the stationary position of the mold and comprises a lower metal plate BI and an upper metal plate 62. A cylindrical sleeve 64 is vertically mounted on plate 6|. Cylindrical member 46 slidably engages mold member I4 through aperture 63 and also passes through and slidably engages stationary sleeve 64. Guide post 45 is fixedly held in mold member [4 and extends on either side thereof. As previously mentioned, the lower extension of post 45 engages bearing 44 of mold member l5. The upper portion of post 45 extends into aperture 4| of mold member 12.

Mold member l3 comprises a lower metal plate 65 attached to an upper plate 66 in which bearing members 61 and 68 are positioned. Mold member I3 slidably engages stationary sleeve 64 and posts 2! and 45, and is movable up or down in a vertical direction.

The operation of my novel injection mold for framing lenses will now be further described: Mold blocks I l and I would be suitably attached to the respective faces of pistons of an injection molding machine which are adapted to open and close injection molds and would be moved so that the mold parts would assume the positions, for example, as shown in Fig. 1, and sufficiently so that lens 50, which itself may be made of a plastic or glass, could be placed on lower lens support 54. In the operation of this mold, it is desirable that the diameter of the lens 56 be substantially that of the inner diameter of sleeve 64. This prevents horizontal movement of the lens 50 which is not desired in this type of molding operation.

With the lens 50 thus positioned on member 54 the injection molding machine would be actuated to cause the mold to close in the sequence shown in Figs. 2 and 3. As shown in Fig. 2, the upper mold block I l is lowered until the ring 25 presses against the surface of lens 50 thereby preventin the lens 56 from being forced out of the sleeve 64 during preliminary mold movement. Assuming lens 50 is thicker along one portion of its edge than other portions, 9, novel effect is produced as the mold closes. The downward force of ring 25 will be exerted on lens 50 which is supported on rockable member 54, which will rock until the lens assumes a fiat position in respect to ring 25. This permits a uniform contact on the lens of ring 25 and rockable member 54 and prevents the plastic which is injected into the mold from flowing over the center portion of the lens. The rod 55 which is attached to rockable member 54 will consequently bend somewhat out of its normal position. Rod 55 also functions to hold rockable member 54 from falling out of the mold during mold opening and closing. Next, lower mold part I5 is moved upwardly as shown in Fig. 3, thereby raising the upper end of cylinder 46 and its associated lens supporting member 54 out of the open end of sleeve 64. This upward movement of cylinder 46 is resisted by the spring pressed ring member 22 but, however, this spring pressure is overcome somewhat and member 22 withdraws to the position shown in Fig. 3. As previously stated, the inner walls of the mold cavity will comprise the surface of lower lens supporting member 54 on the lower side of the lens and the cooperating projection 34 and ring 25 on the upper side of the lens. The other walls of the mold cavity, which is formed on closing of the mold, are evident in Fig. 3. The posts 21 and 45 slidably engage the respective mold blocks and maintain them in proper alignment relation as is evident from the drawings. When the mold is closed, as shown in Fig. 3, and held closed under satisfactory pressure, the injection molding machine, not shown, injects thermoplastic material into the mold cavity through gate 26 until the mold cavity is filled. After the plastic is hardened, as is customary by cooling, the pistons are retracted and the mold block assumes the position shown in Fig. 1 and the lens in its frame is removed from the mold cavity. The operation can now be repeated.

' While only a single cavity mold has been described, it is obvious that a multiple cavity mold could be assembled which would incorporate my novel mold structure as respects one or more mold cavities. In such a, multiple cavity mold, the gate members may be placed in other locations if de-- sired.

Various plastic compounds may be employed to:

form the lens mounting such as thermoplastic or thermosetting resins.

acrylate and methacrylate resins.

What I claim and desire to secure by Letters:

Patent of the United States is:

1. In an injection mold adapted to open and. close and to form an injection mold cavity when closed, and to mold a concentric peripheral plastic mounting on a non-optically centered lens positioned in said cavity, the combination of an upper mold block having a vertically slidable and spring mounted lens clamping member with a lower mold block having a vertically slidable lens clamping member mounted to rock about a point on its vertical axis and a stationary hollow cylindrical member through which the lower rockable lens clamping member slides adapted to restrict horizontal movement of a lens placed on said rockable lens clamping member during the initial clamping operation.

2. In an injection mold adapted to open and close and to form an injection mold cavity when closed, and to mold a concentric peripheral plastic mounting on a non-optically centered lens positioned in the cavity, the combination of an upper mold block having a vertically slidable and spring pressed lens clamping member with a lower mold block having a vertically slidable lens clamping member mounted to rock about a point on its vertical axis, and a stationary hollow cylindrical member through which said lens clamping member slides adapted to restrict horizontal movement of a lens placed on said lens clamp during initial clamping movement and adapted to form a portion of the mold cavity wall after complete movement of the coacting lens clamps.

HOWARD G. FAY.

References Cited in the file of this patent UNITED STATES PATENTS Mulcahy Mar. 19, 1940 Cellulose ester compositions such as cellulose acetate may be employed. advantageously as can the various glass-like: 

